On 06/03/11 05:39 PM, Bruce Cran wrote: > On Mon, 7 Mar 2011 05:00:42 +0800 > Adrian Chadd <[email protected]> wrote: > > >> FreeBSD doesn't implement OFDM in the kernel. >> >> The various chipsets implement OFDM, not FreeBSD. >> >> There's no "software" OFDM. The 802.11 chipsets out there take care >> of it, not FreeBSD. >> > [moved to freebsd-chat] > > OFDM doesn't exist in the digital domain. The furthest you can go in > software is to use the I-Q pairs that represent the modulated (baseband) > data - that is, QPSK, BPSK, QAM etc. If you have a card that makes I-Q > data accessible (and I suspect most wireless cards don't) then you can > demodulate it using general-purpose software such as Matlab or a DSP > library. > > you don't need to make the transformations at the digital domain: only time domain is really what you need in a pure sinusoidal function so you could compute the reverse using sin-1. Therefore no need to go further than the OFDM layer where a custom CPU (the kernel) could 'capture' the raw 802.11 data stream and modulate an invert current according to this variable bitrate in Mb/s.
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